Multiple-input multiple-output (MIMO) wireless systems exploiting multiple antennas as both transmitters and receivers have attracted increasing interest due to their potential for increased capacity in rich multipath environments. Such systems can be used to enable enhanced communication performance (i.e. improved signal quality and reliability) by use of multi-path propagation without additional spectrum requirements. This has been a well-known and well-used solution to achieve high data rate communications in relation to 2G and 3G communication standards. For indoor wireless applications such as router devices, external dipole and monopole antennas are widely used. In this instance, high-gain, omni-directional dipole arrays and collinear antennas are most popular. However, very few portable devices with MIMO capability are available in the marketplace. The main reason for this is that, when gathering several radiators in a portable device, the small allocated space for the antenna limits the ability to provide adequate isolation between each radiator.
The applicants have described a first reconfigurable MIMO antenna in WO2012/072969. An embodiment is described in which the antenna comprises a balanced antenna located at a first end of a PCB and a two-port chassis-antenna located at an opposite second end of the PCB. However, in certain applications this configuration may not be ideal or even practical since it requires two separate areas in which to locate each antenna. However, as mentioned above this spacing was chosen to provide adequate isolation between each antenna structure.
An aim of the present invention is therefore to provide a reconfigurable antenna which helps to address the above-mentioned problems.